Don Casey Tip #37

Varnish Coating Schedule for Exterior Brightwork

The following coating schedule for applying varnish is offered as guidance, not gospel, but following it will nearly always yield a head-turning finish.

• Coat 1: Thin about 50% with the specified thinner.  This is the sealer coat.  Allow to dry overnight.
• Coat 2: Thin 20% with specified thinner. Do not sand sealer coat before applying coat 2.  Let dry 24 hours.
• Coat 3: Thin 10%. Apply over coat 2 without sanding. Let dry 24 hours.
• Coat 4: Sand coat 3 lightly with 220-grit paper. Apply varnish full strength. Allow to dry for at least two nights.
• Coats 5 & 6: Same as coat 4 except sand between coats more heavily to "plane" the surface smooth. Flat surfaces may be sanded with an orbital sander.
• Coats 7, 8, and 9: Sand by hand with 320-grit paper between coats. Apply varnish full strength, taking extra care to avoid runs and sags. Allow each application to dry over at least three nights before overcoating.

Coats 1 through 6 can be your finish varnish or a less expensive formulation, but do not use hardware store varnish. General-purpose varnishes are typically too brittle for marine use.  In hot weather coats 4 through 9 may require a small amount of thinner to keep the brush from "dragging."